scripts/mod/modpost.c

   1 /* Postprocess module symbol versions
   2  *
   3  * Copyright 2003       Kai Germaschewski
   4  * Copyright 2002-2004  Rusty Russell, IBM Corporation
   5  * Copyright 2006-2008  Sam Ravnborg
   6  * Based in part on module-init-tools/depmod.c,file2alias
   7  *
   8  * This software may be used and distributed according to the terms
   9  * of the GNU General Public License, incorporated herein by reference.
  10  *
  11  * Usage: modpost vmlinux module1.o module2.o ...
  12  */
  13
  14 #define _GNU_SOURCE
  15 #include <stdio.h>
  16 #include <ctype.h>
  17 #include <string.h>
  18 #include <limits.h>
  19 #include <stdbool.h>
  20 #include <errno.h>
  21 #include "modpost.h"
  22 #include "../../include/linux/license.h"
  23
  24 /* Are we using CONFIG_MODVERSIONS? */
  25 static int modversions = 0;
  26 /* Warn about undefined symbols? (do so if we have vmlinux) */
  27 static int have_vmlinux = 0;
  28 /* Is CONFIG_MODULE_SRCVERSION_ALL set? */
  29 static int all_versions = 0;
  30 /* If we are modposting external module set to 1 */
  31 static int external_module = 0;
  32 /* Warn about section mismatch in vmlinux if set to 1 */
  33 static int vmlinux_section_warnings = 1;
  34 /* Only warn about unresolved symbols */
  35 static int warn_unresolved = 0;
  36 /* How a symbol is exported */
  37 static int sec_mismatch_count = 0;
  38 static int sec_mismatch_verbose = 1;
  39 static int sec_mismatch_fatal = 0;
  40 /* ignore missing files */
  41 static int ignore_missing_files;
  42
  43 enum export {
  44         export_plain,      export_unused,     export_gpl,
  45         export_unused_gpl, export_gpl_future, export_unknown
  46 };
  47
  48 /* In kernel, this size is defined in linux/module.h;
  49  * here we use Elf_Addr instead of long for covering cross-compile
  50  */
  51
  52 #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
  53
  54 #define PRINTF __attribute__ ((format (printf, 1, 2)))
  55
  56 PRINTF void fatal(const char *fmt, ...)
  57 {
  58         va_list arglist;
  59
  60         fprintf(stderr, "FATAL: ");
  61
  62         va_start(arglist, fmt);
  63         vfprintf(stderr, fmt, arglist);
  64         va_end(arglist);
  65
  66         exit(1);
  67 }
  68
  69 PRINTF void warn(const char *fmt, ...)
  70 {
  71         va_list arglist;
  72
  73         fprintf(stderr, "WARNING: ");
  74
  75         va_start(arglist, fmt);
  76         vfprintf(stderr, fmt, arglist);
  77         va_end(arglist);
  78 }
  79
  80 PRINTF void merror(const char *fmt, ...)
  81 {
  82         va_list arglist;
  83
  84         fprintf(stderr, "ERROR: ");
  85
  86         va_start(arglist, fmt);
  87         vfprintf(stderr, fmt, arglist);
  88         va_end(arglist);
  89 }
  90
  91 static inline bool strends(const char *str, const char *postfix)
  92 {
  93         if (strlen(str) < strlen(postfix))
  94                 return false;
  95
  96         return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0;
  97 }
  98
  99 static int is_vmlinux(const char *modname)
 100 {
 101         const char *myname;
 102
 103         myname = strrchr(modname, '/');
 104         if (myname)
 105                 myname++;
 106         else
 107                 myname = modname;
 108
 109         return (strcmp(myname, "vmlinux") == 0) ||
 110                (strcmp(myname, "vmlinux.o") == 0);
 111 }
 112
 113 void *do_nofail(void *ptr, const char *expr)
 114 {
 115         if (!ptr)
 116                 fatal("modpost: Memory allocation failure: %s.\n", expr);
 117
 118         return ptr;
 119 }
 120
 121 /* A list of all modules we processed */
 122 static struct module *modules;
 123
 124 static struct module *find_module(const char *modname)
 125 {
 126         struct module *mod;
 127
 128         for (mod = modules; mod; mod = mod->next)
 129                 if (strcmp(mod->name, modname) == 0)
 130                         break;
 131         return mod;
 132 }
 133
 134 static struct module *new_module(const char *modname)
 135 {
 136         struct module *mod;
 137         char *p;
 138
 139         mod = NOFAIL(malloc(sizeof(*mod)));
 140         memset(mod, 0, sizeof(*mod));
 141         p = NOFAIL(strdup(modname));
 142
 143         /* strip trailing .o */
 144         if (strends(p, ".o")) {
 145                 p[strlen(p) - 2] = '\0';
 146                 mod->is_dot_o = 1;
 147         }
 148
 149         /* add to list */
 150         mod->name = p;
 151         mod->gpl_compatible = -1;
 152         mod->next = modules;
 153         modules = mod;
 154
 155         return mod;
 156 }
 157
 158 /* A hash of all exported symbols,
 159  * struct symbol is also used for lists of unresolved symbols */
 160
 161 #define SYMBOL_HASH_SIZE 1024
 162
 163 struct symbol {
 164         struct symbol *next;
 165         struct module *module;
 166         unsigned int crc;
 167         int crc_valid;
 168         unsigned int weak:1;
 169         unsigned int vmlinux:1;    /* 1 if symbol is defined in vmlinux */
 170         unsigned int kernel:1;     /* 1 if symbol is from kernel
 171                                     *  (only for external modules) **/
 172         unsigned int preloaded:1;  /* 1 if symbol from Module.symvers, or crc */
 173         enum export  export;       /* Type of export */
 174         char name[0];
 175 };
 176
 177 static struct symbol *symbolhash[SYMBOL_HASH_SIZE];
 178
 179 /* This is based on the hash agorithm from gdbm, via tdb */
 180 static inline unsigned int tdb_hash(const char *name)
 181 {
 182         unsigned value; /* Used to compute the hash value.  */
 183         unsigned   i;   /* Used to cycle through random values. */
 184
 185         /* Set the initial value from the key size. */
 186         for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++)
 187                 value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));
 188
 189         return (1103515243 * value + 12345);
 190 }
 191
 192 /**
 193  * Allocate a new symbols for use in the hash of exported symbols or
 194  * the list of unresolved symbols per module
 195  **/
 196 static struct symbol *alloc_symbol(const char *name, unsigned int weak,
 197                                    struct symbol *next)
 198 {
 199         struct symbol *s = NOFAIL(malloc(sizeof(*s) + strlen(name) + 1));
 200
 201         memset(s, 0, sizeof(*s));
 202         strcpy(s->name, name);
 203         s->weak = weak;
 204         s->next = next;
 205         return s;
 206 }
 207
 208 /* For the hash of exported symbols */
 209 static struct symbol *new_symbol(const char *name, struct module *module,
 210                                  enum export export)
 211 {
 212         unsigned int hash;
 213         struct symbol *new;
 214
 215         hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
 216         new = symbolhash[hash] = alloc_symbol(name, 0, symbolhash[hash]);
 217         new->module = module;
 218         new->export = export;
 219         return new;
 220 }
 221
 222 static struct symbol *find_symbol(const char *name)
 223 {
 224         struct symbol *s;
 225
 226         /* For our purposes, .foo matches foo.  PPC64 needs this. */
 227         if (name[0] == '.')
 228                 name++;
 229
 230         for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s = s->next) {
 231                 if (strcmp(s->name, name) == 0)
 232                         return s;
 233         }
 234         return NULL;
 235 }
 236
 237 static const struct {
 238         const char *str;
 239         enum export export;
 240 } export_list[] = {
 241         { .str = "EXPORT_SYMBOL",            .export = export_plain },
 242         { .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },
 243         { .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },
 244         { .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
 245         { .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
 246         { .str = "(unknown)",                .export = export_unknown },
 247 };
 248
 249
 250 static const char *export_str(enum export ex)
 251 {
 252         return export_list[ex].str;
 253 }
 254
 255 static enum export export_no(const char *s)
 256 {
 257         int i;
 258
 259         if (!s)
 260                 return export_unknown;
 261         for (i = 0; export_list[i].export != export_unknown; i++) {
 262                 if (strcmp(export_list[i].str, s) == 0)
 263                         return export_list[i].export;
 264         }
 265         return export_unknown;
 266 }
 267
 268 static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr)
 269 {
 270         return (void *)elf->hdr +
 271                 elf->sechdrs[elf->secindex_strings].sh_offset +
 272                 sechdr->sh_name;
 273 }
 274
 275 static const char *sec_name(struct elf_info *elf, int secindex)
 276 {
 277         return sech_name(elf, &elf->sechdrs[secindex]);
 278 }
 279
 280 #define strstarts(str, prefix) (strncmp(str, prefix, strlen(prefix)) == 0)
 281
 282 static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
 283 {
 284         const char *secname = sec_name(elf, sec);
 285
 286         if (strstarts(secname, "___ksymtab+"))
 287                 return export_plain;
 288         else if (strstarts(secname, "___ksymtab_unused+"))
 289                 return export_unused;
 290         else if (strstarts(secname, "___ksymtab_gpl+"))
 291                 return export_gpl;
 292         else if (strstarts(secname, "___ksymtab_unused_gpl+"))
 293                 return export_unused_gpl;
 294         else if (strstarts(secname, "___ksymtab_gpl_future+"))
 295                 return export_gpl_future;
 296         else
 297                 return export_unknown;
 298 }
 299
 300 static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
 301 {
 302         if (sec == elf->export_sec)
 303                 return export_plain;
 304         else if (sec == elf->export_unused_sec)
 305                 return export_unused;
 306         else if (sec == elf->export_gpl_sec)
 307                 return export_gpl;
 308         else if (sec == elf->export_unused_gpl_sec)
 309                 return export_unused_gpl;
 310         else if (sec == elf->export_gpl_future_sec)
 311                 return export_gpl_future;
 312         else
 313                 return export_unknown;
 314 }
 315
 316 /**
 317  * Add an exported symbol - it may have already been added without a
 318  * CRC, in this case just update the CRC
 319  **/
 320 static struct symbol *sym_add_exported(const char *name, struct module *mod,
 321                                        enum export export)
 322 {
 323         struct symbol *s = find_symbol(name);
 324
 325         if (!s) {
 326                 s = new_symbol(name, mod, export);
 327         } else {
 328                 if (!s->preloaded) {
 329                         warn("%s: '%s' exported twice. Previous export "
 330                              "was in %s%s\n", mod->name, name,
 331                              s->module->name,
 332                              is_vmlinux(s->module->name) ?"":".ko");
 333                 } else {
 334                         /* In case Module.symvers was out of date */
 335                         s->module = mod;
 336                 }
 337         }
 338         s->preloaded = 0;
 339         s->vmlinux   = is_vmlinux(mod->name);
 340         s->kernel    = 0;
 341         s->export    = export;
 342         return s;
 343 }
 344
 345 static void sym_update_crc(const char *name, struct module *mod,
 346                            unsigned int crc, enum export export)
 347 {
 348         struct symbol *s = find_symbol(name);
 349
 350         if (!s) {
 351                 s = new_symbol(name, mod, export);
 352                 /* Don't complain when we find it later. */
 353                 s->preloaded = 1;
 354         }
 355         s->crc = crc;
 356         s->crc_valid = 1;
 357 }
 358
 359 void *grab_file(const char *filename, unsigned long *size)
 360 {
 361         struct stat st;
 362         void *map = MAP_FAILED;
 363         int fd;
 364
 365         fd = open(filename, O_RDONLY);
 366         if (fd < 0)
 367                 return NULL;
 368         if (fstat(fd, &st))
 369                 goto failed;
 370
 371         *size = st.st_size;
 372         map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
 373
 374 failed:
 375         close(fd);
 376         if (map == MAP_FAILED)
 377                 return NULL;
 378         return map;
 379 }
 380
 381 /**
 382   * Return a copy of the next line in a mmap'ed file.
 383   * spaces in the beginning of the line is trimmed away.
 384   * Return a pointer to a static buffer.
 385   **/
 386 char *get_next_line(unsigned long *pos, void *file, unsigned long size)
 387 {
 388         static char line[4096];
 389         int skip = 1;
 390         size_t len = 0;
 391         signed char *p = (signed char *)file + *pos;
 392         char *s = line;
 393
 394         for (; *pos < size ; (*pos)++) {
 395                 if (skip && isspace(*p)) {
 396                         p++;
 397                         continue;
 398                 }
 399                 skip = 0;
 400                 if (*p != '\n' && (*pos < size)) {
 401                         len++;
 402                         *s++ = *p++;
 403                         if (len > 4095)
 404                                 break; /* Too long, stop */
 405                 } else {
 406                         /* End of string */
 407                         *s = '\0';
 408                         return line;
 409                 }
 410         }
 411         /* End of buffer */
 412         return NULL;
 413 }
 414
 415 void release_file(void *file, unsigned long size)
 416 {
 417         munmap(file, size);
 418 }
 419
 420 static int parse_elf(struct elf_info *info, const char *filename)
 421 {
 422         unsigned int i;
 423         Elf_Ehdr *hdr;
 424         Elf_Shdr *sechdrs;
 425         Elf_Sym  *sym;
 426         const char *secstrings;
 427         unsigned int symtab_idx = ~0U, symtab_shndx_idx = ~0U;
 428
 429         hdr = grab_file(filename, &info->size);
 430         if (!hdr) {
 431                 if (ignore_missing_files) {
 432                         fprintf(stderr, "%s: %s (ignored)\n", filename,
 433                                 strerror(errno));
 434                         return 0;
 435                 }
 436                 perror(filename);
 437                 exit(1);
 438         }
 439         info->hdr = hdr;
 440         if (info->size < sizeof(*hdr)) {
 441                 /* file too small, assume this is an empty .o file */
 442                 return 0;
 443         }
 444         /* Is this a valid ELF file? */
 445         if ((hdr->e_ident[EI_MAG0] != ELFMAG0) ||
 446             (hdr->e_ident[EI_MAG1] != ELFMAG1) ||
 447             (hdr->e_ident[EI_MAG2] != ELFMAG2) ||
 448             (hdr->e_ident[EI_MAG3] != ELFMAG3)) {
 449                 /* Not an ELF file - silently ignore it */
 450                 return 0;
 451         }
 452         /* Fix endianness in ELF header */
 453         hdr->e_type      = TO_NATIVE(hdr->e_type);
 454         hdr->e_machine   = TO_NATIVE(hdr->e_machine);
 455         hdr->e_version   = TO_NATIVE(hdr->e_version);
 456         hdr->e_entry     = TO_NATIVE(hdr->e_entry);
 457         hdr->e_phoff     = TO_NATIVE(hdr->e_phoff);
 458         hdr->e_shoff     = TO_NATIVE(hdr->e_shoff);
 459         hdr->e_flags     = TO_NATIVE(hdr->e_flags);
 460         hdr->e_ehsize    = TO_NATIVE(hdr->e_ehsize);
 461         hdr->e_phentsize = TO_NATIVE(hdr->e_phentsize);
 462         hdr->e_phnum     = TO_NATIVE(hdr->e_phnum);
 463         hdr->e_shentsize = TO_NATIVE(hdr->e_shentsize);
 464         hdr->e_shnum     = TO_NATIVE(hdr->e_shnum);
 465         hdr->e_shstrndx  = TO_NATIVE(hdr->e_shstrndx);
 466         sechdrs = (void *)hdr + hdr->e_shoff;
 467         info->sechdrs = sechdrs;
 468
 469         /* Check if file offset is correct */
 470         if (hdr->e_shoff > info->size) {
 471                 fatal("section header offset=%lu in file '%s' is bigger than "
 472                       "filesize=%lu\n", (unsigned long)hdr->e_shoff,
 473                       filename, info->size);
 474                 return 0;
 475         }
 476
 477         if (hdr->e_shnum == SHN_UNDEF) {
 478                 /*
 479                  * There are more than 64k sections,
 480                  * read count from .sh_size.
 481                  */
 482                 info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
 483         }
 484         else {
 485                 info->num_sections = hdr->e_shnum;
 486         }
 487         if (hdr->e_shstrndx == SHN_XINDEX) {
 488                 info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
 489         }
 490         else {
 491                 info->secindex_strings = hdr->e_shstrndx;
 492         }
 493
 494         /* Fix endianness in section headers */
 495         for (i = 0; i < info->num_sections; i++) {
 496                 sechdrs[i].sh_name      = TO_NATIVE(sechdrs[i].sh_name);
 497                 sechdrs[i].sh_type      = TO_NATIVE(sechdrs[i].sh_type);
 498                 sechdrs[i].sh_flags     = TO_NATIVE(sechdrs[i].sh_flags);
 499                 sechdrs[i].sh_addr      = TO_NATIVE(sechdrs[i].sh_addr);
 500                 sechdrs[i].sh_offset    = TO_NATIVE(sechdrs[i].sh_offset);
 501                 sechdrs[i].sh_size      = TO_NATIVE(sechdrs[i].sh_size);
 502                 sechdrs[i].sh_link      = TO_NATIVE(sechdrs[i].sh_link);
 503                 sechdrs[i].sh_info      = TO_NATIVE(sechdrs[i].sh_info);
 504                 sechdrs[i].sh_addralign = TO_NATIVE(sechdrs[i].sh_addralign);
 505                 sechdrs[i].sh_entsize   = TO_NATIVE(sechdrs[i].sh_entsize);
 506         }
 507         /* Find symbol table. */
 508         secstrings = (void *)hdr + sechdrs[info->secindex_strings].sh_offset;
 509         for (i = 1; i < info->num_sections; i++) {
 510                 const char *secname;
 511                 int nobits = sechdrs[i].sh_type == SHT_NOBITS;
 512
 513                 if (!nobits && sechdrs[i].sh_offset > info->size) {
 514                         fatal("%s is truncated. sechdrs[i].sh_offset=%lu > "
 515                               "sizeof(*hrd)=%zu\n", filename,
 516                               (unsigned long)sechdrs[i].sh_offset,
 517                               sizeof(*hdr));
 518                         return 0;
 519                 }
 520                 secname = secstrings + sechdrs[i].sh_name;
 521                 if (strcmp(secname, ".modinfo") == 0) {
 522                         if (nobits)
 523                                 fatal("%s has NOBITS .modinfo\n", filename);
 524                         info->modinfo = (void *)hdr + sechdrs[i].sh_offset;
 525                         info->modinfo_len = sechdrs[i].sh_size;
 526                 } else if (strcmp(secname, "__ksymtab") == 0)
 527                         info->export_sec = i;
 528                 else if (strcmp(secname, "__ksymtab_unused") == 0)
 529                         info->export_unused_sec = i;
 530                 else if (strcmp(secname, "__ksymtab_gpl") == 0)
 531                         info->export_gpl_sec = i;
 532                 else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
 533                         info->export_unused_gpl_sec = i;
 534                 else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
 535                         info->export_gpl_future_sec = i;
 536
 537                 if (sechdrs[i].sh_type == SHT_SYMTAB) {
 538                         unsigned int sh_link_idx;
 539                         symtab_idx = i;
 540                         info->symtab_start = (void *)hdr +
 541                             sechdrs[i].sh_offset;
 542                         info->symtab_stop  = (void *)hdr +
 543                             sechdrs[i].sh_offset + sechdrs[i].sh_size;
 544                         sh_link_idx = sechdrs[i].sh_link;
 545                         info->strtab       = (void *)hdr +
 546                             sechdrs[sh_link_idx].sh_offset;
 547                 }
 548
 549                 /* 32bit section no. table? ("more than 64k sections") */
 550                 if (sechdrs[i].sh_type == SHT_SYMTAB_SHNDX) {
 551                         symtab_shndx_idx = i;
 552                         info->symtab_shndx_start = (void *)hdr +
 553                             sechdrs[i].sh_offset;
 554                         info->symtab_shndx_stop  = (void *)hdr +
 555                             sechdrs[i].sh_offset + sechdrs[i].sh_size;
 556                 }
 557         }
 558         if (!info->symtab_start)
 559                 fatal("%s has no symtab?\n", filename);
 560
 561         /* Fix endianness in symbols */
 562         for (sym = info->symtab_start; sym < info->symtab_stop; sym++) {
 563                 sym->st_shndx = TO_NATIVE(sym->st_shndx);
 564                 sym->st_name  = TO_NATIVE(sym->st_name);
 565                 sym->st_value = TO_NATIVE(sym->st_value);
 566                 sym->st_size  = TO_NATIVE(sym->st_size);
 567         }
 568
 569         if (symtab_shndx_idx != ~0U) {
 570                 Elf32_Word *p;
 571                 if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
 572                         fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
 573                               filename, sechdrs[symtab_shndx_idx].sh_link,
 574                               symtab_idx);
 575                 /* Fix endianness */
 576                 for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
 577                      p++)
 578                         *p = TO_NATIVE(*p);
 579         }
 580
 581         return 1;
 582 }
 583
 584 static void parse_elf_finish(struct elf_info *info)
 585 {
 586         release_file(info->hdr, info->size);
 587 }
 588
 589 static int ignore_undef_symbol(struct elf_info *info, const char *symname)
 590 {
 591         /* ignore __this_module, it will be resolved shortly */
 592         if (strcmp(symname, "__this_module") == 0)
 593                 return 1;
 594         /* ignore global offset table */
 595         if (strcmp(symname, "_GLOBAL_OFFSET_TABLE_") == 0)
 596                 return 1;
 597         if (info->hdr->e_machine == EM_PPC)
 598                 /* Special register function linked on all modules during final link of .ko */
 599                 if (strstarts(symname, "_restgpr_") ||
 600                     strstarts(symname, "_savegpr_") ||
 601                     strstarts(symname, "_rest32gpr_") ||
 602                     strstarts(symname, "_save32gpr_") ||
 603                     strstarts(symname, "_restvr_") ||
 604                     strstarts(symname, "_savevr_"))
 605                         return 1;
 606         if (info->hdr->e_machine == EM_PPC64)
 607                 /* Special register function linked on all modules during final link of .ko */
 608                 if (strstarts(symname, "_restgpr0_") ||
 609                     strstarts(symname, "_savegpr0_") ||
 610                     strstarts(symname, "_restvr_") ||
 611                     strstarts(symname, "_savevr_") ||
 612                     strcmp(symname, ".TOC.") == 0)
 613                         return 1;
 614         /* Do not ignore this symbol */
 615         return 0;
 616 }
 617
 618 static void handle_modversions(struct module *mod, struct elf_info *info,
 619                                Elf_Sym *sym, const char *symname)
 620 {
 621         unsigned int crc;
 622         enum export export;
 623         bool is_crc = false;
 624
 625         if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
 626             strstarts(symname, "__ksymtab"))
 627                 export = export_from_secname(info, get_secindex(info, sym));
 628         else
 629                 export = export_from_sec(info, get_secindex(info, sym));
 630
 631         /* CRC'd symbol */
 632         if (strstarts(symname, "__crc_")) {
 633                 is_crc = true;
 634                 crc = (unsigned int) sym->st_value;
 635                 if (sym->st_shndx != SHN_UNDEF && sym->st_shndx != SHN_ABS) {
 636                         unsigned int *crcp;
 637
 638                         /* symbol points to the CRC in the ELF object */
 639                         crcp = (void *)info->hdr + sym->st_value +
 640                                info->sechdrs[sym->st_shndx].sh_offset -
 641                                (info->hdr->e_type != ET_REL ?
 642                                 info->sechdrs[sym->st_shndx].sh_addr : 0);
 643                         crc = TO_NATIVE(*crcp);
 644                 }
 645                 sym_update_crc(symname + strlen("__crc_"), mod, crc,
 646                                 export);
 647         }
 648
 649         switch (sym->st_shndx) {
 650         case SHN_COMMON:
 651                 if (strstarts(symname, "__gnu_lto_")) {
 652                         /* Should warn here, but modpost runs before the linker */
 653                 } else
 654                         warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name);
 655                 break;
 656         case SHN_UNDEF:
 657                 /* undefined symbol */
 658                 if (ELF_ST_BIND(sym->st_info) != STB_GLOBAL &&
 659                     ELF_ST_BIND(sym->st_info) != STB_WEAK)
 660                         break;
 661                 if (ignore_undef_symbol(info, symname))
 662                         break;
 663 /* cope with newer glibc (2.3.4 or higher) STT_ definition in elf.h */
 664 #if defined(STT_REGISTER) || defined(STT_SPARC_REGISTER)
 665 /* add compatibility with older glibc */
 666 #ifndef STT_SPARC_REGISTER
 667 #define STT_SPARC_REGISTER STT_REGISTER
 668 #endif
 669                 if (info->hdr->e_machine == EM_SPARC ||
 670                     info->hdr->e_machine == EM_SPARCV9) {
 671                         /* Ignore register directives. */
 672                         if (ELF_ST_TYPE(sym->st_info) == STT_SPARC_REGISTER)
 673                                 break;
 674                         if (symname[0] == '.') {
 675                                 char *munged = NOFAIL(strdup(symname));
 676                                 munged[0] = '_';
 677                                 munged[1] = toupper(munged[1]);
 678                                 symname = munged;
 679                         }
 680                 }
 681 #endif
 682
 683                 if (is_crc) {
 684                         const char *e = is_vmlinux(mod->name) ?"":".ko";
 685                         warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n",
 686                              symname + strlen("__crc_"), mod->name, e);
 687                 }
 688                 mod->unres = alloc_symbol(symname,
 689                                           ELF_ST_BIND(sym->st_info) == STB_WEAK,
 690                                           mod->unres);
 691                 break;
 692         default:
 693                 /* All exported symbols */
 694                 if (strstarts(symname, "__ksymtab_")) {
 695                         sym_add_exported(symname + strlen("__ksymtab_"), mod,
 696                                         export);
 697                 }
 698                 if (strcmp(symname, "init_module") == 0)
 699                         mod->has_init = 1;
 700                 if (strcmp(symname, "cleanup_module") == 0)
 701                         mod->has_cleanup = 1;
 702                 break;
 703         }
 704 }
 705
 706 /**
 707  * Parse tag=value strings from .modinfo section
 708  **/
 709 static char *next_string(char *string, unsigned long *secsize)
 710 {
 711         /* Skip non-zero chars */
 712         while (string[0]) {
 713                 string++;
 714                 if ((*secsize)-- <= 1)
 715                         return NULL;
 716         }
 717
 718         /* Skip any zero padding. */
 719         while (!string[0]) {
 720                 string++;
 721                 if ((*secsize)-- <= 1)
 722                         return NULL;
 723         }
 724         return string;
 725 }
 726
 727 static char *get_next_modinfo(struct elf_info *info, const char *tag,
 728                               char *prev)
 729 {
 730         char *p;
 731         unsigned int taglen = strlen(tag);
 732         char *modinfo = info->modinfo;
 733         unsigned long size = info->modinfo_len;
 734
 735         if (prev) {
 736                 size -= prev - modinfo;
 737                 modinfo = next_string(prev, &size);
 738         }
 739
 740         for (p = modinfo; p; p = next_string(p, &size)) {
 741                 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
 742                         return p + taglen + 1;
 743         }
 744         return NULL;
 745 }
 746
 747 static char *get_modinfo(struct elf_info *info, const char *tag)
 748
 749 {
 750         return get_next_modinfo(info, tag, NULL);
 751 }
 752
 753 /**
 754  * Test if string s ends in string sub
 755  * return 0 if match
 756  **/
 757 static int strrcmp(const char *s, const char *sub)
 758 {
 759         int slen, sublen;
 760
 761         if (!s || !sub)
 762                 return 1;
 763
 764         slen = strlen(s);
 765         sublen = strlen(sub);
 766
 767         if ((slen == 0) || (sublen == 0))
 768                 return 1;
 769
 770         if (sublen > slen)
 771                 return 1;
 772
 773         return memcmp(s + slen - sublen, sub, sublen);
 774 }
 775
 776 static const char *sym_name(struct elf_info *elf, Elf_Sym *sym)
 777 {
 778         if (sym)
 779                 return elf->strtab + sym->st_name;
 780         else
 781                 return "(unknown)";
 782 }
 783
 784 /* The pattern is an array of simple patterns.
 785  * "foo" will match an exact string equal to "foo"
 786  * "*foo" will match a string that ends with "foo"
 787  * "foo*" will match a string that begins with "foo"
 788  * "*foo*" will match a string that contains "foo"
 789  */
 790 static int match(const char *sym, const char * const pat[])
 791 {
 792         const char *p;
 793         while (*pat) {
 794                 p = *pat++;
 795                 const char *endp = p + strlen(p) - 1;
 796
 797                 /* "*foo*" */
 798                 if (*p == '*' && *endp == '*') {
 799                         char *here, *bare = strndup(p + 1, strlen(p) - 2);
 800
 801                         here = strstr(sym, bare);
 802                         free(bare);
 803                         if (here != NULL)
 804                                 return 1;
 805                 }
 806                 /* "*foo" */
 807                 else if (*p == '*') {
 808                         if (strrcmp(sym, p + 1) == 0)
 809                                 return 1;
 810                 }
 811                 /* "foo*" */
 812                 else if (*endp == '*') {
 813                         if (strncmp(sym, p, strlen(p) - 1) == 0)
 814                                 return 1;
 815                 }
 816                 /* no wildcards */
 817                 else {
 818                         if (strcmp(p, sym) == 0)
 819                                 return 1;
 820                 }
 821         }
 822         /* no match */
 823         return 0;
 824 }
 825
 826 /* sections that we do not want to do full section mismatch check on */
 827 static const char *const section_white_list[] =
 828 {
 829         ".comment*",
 830         ".debug*",
 831         ".cranges",             /* sh64 */
 832         ".zdebug*",             /* Compressed debug sections. */
 833         ".GCC.command.line",    /* record-gcc-switches */
 834         ".mdebug*",        /* alpha, score, mips etc. */
 835         ".pdr",            /* alpha, score, mips etc. */
 836         ".stab*",
 837         ".note*",
 838         ".got*",
 839         ".toc*",
 840         ".xt.prop",                              /* xtensa */
 841         ".xt.lit",         /* xtensa */
 842         ".arcextmap*",                  /* arc */
 843         ".gnu.linkonce.arcext*",        /* arc : modules */
 844         ".cmem*",                       /* EZchip */
 845         ".fmt_slot*",                   /* EZchip */
 846         ".gnu.lto*",
 847         ".discard.*",
 848         NULL
 849 };
 850
 851 /*
 852  * This is used to find sections missing the SHF_ALLOC flag.
 853  * The cause of this is often a section specified in assembler
 854  * without "ax" / "aw".
 855  */
 856 static void check_section(const char *modname, struct elf_info *elf,
 857                           Elf_Shdr *sechdr)
 858 {
 859         const char *sec = sech_name(elf, sechdr);
 860
 861         if (sechdr->sh_type == SHT_PROGBITS &&
 862             !(sechdr->sh_flags & SHF_ALLOC) &&
 863             !match(sec, section_white_list)) {
 864                 warn("%s (%s): unexpected non-allocatable section.\n"
 865                      "Did you forget to use \"ax\"/\"aw\" in a .S file?\n"
 866                      "Note that for example <linux/init.h> contains\n"
 867                      "section definitions for use in .S files.\n\n",
 868                      modname, sec);
 869         }
 870 }
 871
 872
 873
 874 #define ALL_INIT_DATA_SECTIONS \
 875         ".init.setup", ".init.rodata", ".meminit.rodata", \
 876         ".init.data", ".meminit.data"
 877 #define ALL_EXIT_DATA_SECTIONS \
 878         ".exit.data", ".memexit.data"
 879
 880 #define ALL_INIT_TEXT_SECTIONS \
 881         ".init.text", ".meminit.text"
 882 #define ALL_EXIT_TEXT_SECTIONS \
 883         ".exit.text", ".memexit.text"
 884
 885 #define ALL_PCI_INIT_SECTIONS   \
 886         ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \
 887         ".pci_fixup_enable", ".pci_fixup_resume", \
 888         ".pci_fixup_resume_early", ".pci_fixup_suspend"
 889
 890 #define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS
 891 #define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS
 892
 893 #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS
 894 #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS
 895
 896 #define DATA_SECTIONS ".data", ".data.rel"
 897 #define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \
 898                 ".kprobes.text", ".cpuidle.text", ".noinstr.text"
 899 #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \
 900                 ".fixup", ".entry.text", ".exception.text", ".text.*", \
 901                 ".coldtext"
 902
 903 #define INIT_SECTIONS      ".init.*"
 904 #define MEM_INIT_SECTIONS  ".meminit.*"
 905
 906 #define EXIT_SECTIONS      ".exit.*"
 907 #define MEM_EXIT_SECTIONS  ".memexit.*"
 908
 909 #define ALL_TEXT_SECTIONS  ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \
 910                 TEXT_SECTIONS, OTHER_TEXT_SECTIONS
 911
 912 /* init data sections */
 913 static const char *const init_data_sections[] =
 914         { ALL_INIT_DATA_SECTIONS, NULL };
 915
 916 /* all init sections */
 917 static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL };
 918
 919 /* All init and exit sections (code + data) */
 920 static const char *const init_exit_sections[] =
 921         {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL };
 922
 923 /* all text sections */
 924 static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL };
 925
 926 /* data section */
 927 static const char *const data_sections[] = { DATA_SECTIONS, NULL };
 928
 929
 930 /* symbols in .data that may refer to init/exit sections */
 931 #define DEFAULT_SYMBOL_WHITE_LIST                                       \
 932         "*driver",                                                      \
 933         "*_template", /* scsi uses *_template a lot */                  \
 934         "*_timer",    /* arm uses ops structures named _timer a lot */  \
 935         "*_sht",      /* scsi also used *_sht to some extent */         \
 936         "*_ops",                                                        \
 937         "*_probe",                                                      \
 938         "*_probe_one",                                                  \
 939         "*_console"
 940
 941 static const char *const head_sections[] = { ".head.text*", NULL };
 942 static const char *const linker_symbols[] =
 943         { "__init_begin", "_sinittext", "_einittext", NULL };
 944 static const char *const optim_symbols[] = { "*.constprop.*", NULL };
 945
 946 enum mismatch {
 947         TEXT_TO_ANY_INIT,
 948         DATA_TO_ANY_INIT,
 949         TEXT_TO_ANY_EXIT,
 950         DATA_TO_ANY_EXIT,
 951         XXXINIT_TO_SOME_INIT,
 952         XXXEXIT_TO_SOME_EXIT,
 953         ANY_INIT_TO_ANY_EXIT,
 954         ANY_EXIT_TO_ANY_INIT,
 955         EXPORT_TO_INIT_EXIT,
 956         EXTABLE_TO_NON_TEXT,
 957 };
 958
 959 /**
 960  * Describe how to match sections on different criterias:
 961  *
 962  * @fromsec: Array of sections to be matched.
 963  *
 964  * @bad_tosec: Relocations applied to a section in @fromsec to a section in
 965  * this array is forbidden (black-list).  Can be empty.
 966  *
 967  * @good_tosec: Relocations applied to a section in @fromsec must be
 968  * targetting sections in this array (white-list).  Can be empty.
 969  *
 970  * @mismatch: Type of mismatch.
 971  *
 972  * @symbol_white_list: Do not match a relocation to a symbol in this list
 973  * even if it is targetting a section in @bad_to_sec.
 974  *
 975  * @handler: Specific handler to call when a match is found.  If NULL,
 976  * default_mismatch_handler() will be called.
 977  *
 978  */
 979 struct sectioncheck {
 980         const char *fromsec[20];
 981         const char *bad_tosec[20];
 982         const char *good_tosec[20];
 983         enum mismatch mismatch;
 984         const char *symbol_white_list[20];
 985         void (*handler)(const char *modname, struct elf_info *elf,
 986                         const struct sectioncheck* const mismatch,
 987                         Elf_Rela *r, Elf_Sym *sym, const char *fromsec);
 988
 989 };
 990
 991 static void extable_mismatch_handler(const char *modname, struct elf_info *elf,
 992                                      const struct sectioncheck* const mismatch,
 993                                      Elf_Rela *r, Elf_Sym *sym,
 994                                      const char *fromsec);
 995
 996 static const struct sectioncheck sectioncheck[] = {
 997 /* Do not reference init/exit code/data from
 998  * normal code and data
 999  */
1000 {
1001         .fromsec = { TEXT_SECTIONS, NULL },
1002         .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1003         .mismatch = TEXT_TO_ANY_INIT,
1004         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1005 },
1006 {
1007         .fromsec = { DATA_SECTIONS, NULL },
1008         .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL },
1009         .mismatch = DATA_TO_ANY_INIT,
1010         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1011 },
1012 {
1013         .fromsec = { DATA_SECTIONS, NULL },
1014         .bad_tosec = { INIT_SECTIONS, NULL },
1015         .mismatch = DATA_TO_ANY_INIT,
1016         .symbol_white_list = {
1017                 "*_template", "*_timer", "*_sht", "*_ops",
1018                 "*_probe", "*_probe_one", "*_console", NULL
1019         },
1020 },
1021 {
1022         .fromsec = { TEXT_SECTIONS, NULL },
1023         .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1024         .mismatch = TEXT_TO_ANY_EXIT,
1025         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1026 },
1027 {
1028         .fromsec = { DATA_SECTIONS, NULL },
1029         .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1030         .mismatch = DATA_TO_ANY_EXIT,
1031         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1032 },
1033 /* Do not reference init code/data from meminit code/data */
1034 {
1035         .fromsec = { ALL_XXXINIT_SECTIONS, NULL },
1036         .bad_tosec = { INIT_SECTIONS, NULL },
1037         .mismatch = XXXINIT_TO_SOME_INIT,
1038         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1039 },
1040 /* Do not reference exit code/data from memexit code/data */
1041 {
1042         .fromsec = { ALL_XXXEXIT_SECTIONS, NULL },
1043         .bad_tosec = { EXIT_SECTIONS, NULL },
1044         .mismatch = XXXEXIT_TO_SOME_EXIT,
1045         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1046 },
1047 /* Do not use exit code/data from init code */
1048 {
1049         .fromsec = { ALL_INIT_SECTIONS, NULL },
1050         .bad_tosec = { ALL_EXIT_SECTIONS, NULL },
1051         .mismatch = ANY_INIT_TO_ANY_EXIT,
1052         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1053 },
1054 /* Do not use init code/data from exit code */
1055 {
1056         .fromsec = { ALL_EXIT_SECTIONS, NULL },
1057         .bad_tosec = { ALL_INIT_SECTIONS, NULL },
1058         .mismatch = ANY_EXIT_TO_ANY_INIT,
1059         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1060 },
1061 {
1062         .fromsec = { ALL_PCI_INIT_SECTIONS, NULL },
1063         .bad_tosec = { INIT_SECTIONS, NULL },
1064         .mismatch = ANY_INIT_TO_ANY_EXIT,
1065         .symbol_white_list = { NULL },
1066 },
1067 /* Do not export init/exit functions or data */
1068 {
1069         .fromsec = { "__ksymtab*", NULL },
1070         .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
1071         .mismatch = EXPORT_TO_INIT_EXIT,
1072         .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL },
1073 },
1074 {
1075         .fromsec = { "__ex_table", NULL },
1076         /* If you're adding any new black-listed sections in here, consider
1077          * adding a special 'printer' for them in scripts/check_extable.
1078          */
1079         .bad_tosec = { ".altinstr_replacement", NULL },
1080         .good_tosec = {ALL_TEXT_SECTIONS , NULL},
1081         .mismatch = EXTABLE_TO_NON_TEXT,
1082         .handler = extable_mismatch_handler,
1083 }
1084 };
1085
1086 static const struct sectioncheck *section_mismatch(
1087                 const char *fromsec, const char *tosec)
1088 {
1089         int i;
1090         int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck);
1091         const struct sectioncheck *check = &sectioncheck[0];
1092
1093         /*
1094          * The target section could be the SHT_NUL section when we're
1095          * handling relocations to un-resolved symbols, trying to match it
1096          * doesn't make much sense and causes build failures on parisc
1097          * architectures.
1098          */
1099         if (*tosec == '\0')
1100                 return NULL;
1101
1102         for (i = 0; i < elems; i++) {
1103                 if (match(fromsec, check->fromsec)) {
1104                         if (check->bad_tosec[0] && match(tosec, check->bad_tosec))
1105                                 return check;
1106                         if (check->good_tosec[0] && !match(tosec, check->good_tosec))
1107                                 return check;
1108                 }
1109                 check++;
1110         }
1111         return NULL;
1112 }
1113
1114 /**
1115  * Whitelist to allow certain references to pass with no warning.
1116  *
1117  * Pattern 1:
1118  *   If a module parameter is declared __initdata and permissions=0
1119  *   then this is legal despite the warning generated.
1120  *   We cannot see value of permissions here, so just ignore
1121  *   this pattern.
1122  *   The pattern is identified by:
1123  *   tosec   = .init.data
1124  *   fromsec = .data*
1125  *   atsym   =__param*
1126  *
1127  * Pattern 1a:
1128  *   module_param_call() ops can refer to __init set function if permissions=0
1129  *   The pattern is identified by:
1130  *   tosec   = .init.text
1131  *   fromsec = .data*
1132  *   atsym   = __param_ops_*
1133  *
1134  * Pattern 2:
1135  *   Many drivers utilise a *driver container with references to
1136  *   add, remove, probe functions etc.
1137  *   the pattern is identified by:
1138  *   tosec   = init or exit section
1139  *   fromsec = data section
1140  *   atsym = *driver, *_template, *_sht, *_ops, *_probe,
1141  *           *probe_one, *_console, *_timer
1142  *
1143  * Pattern 3:
1144  *   Whitelist all references from .head.text to any init section
1145  *
1146  * Pattern 4:
1147  *   Some symbols belong to init section but still it is ok to reference
1148  *   these from non-init sections as these symbols don't have any memory
1149  *   allocated for them and symbol address and value are same. So even
1150  *   if init section is freed, its ok to reference those symbols.
1151  *   For ex. symbols marking the init section boundaries.
1152  *   This pattern is identified by
1153  *   refsymname = __init_begin, _sinittext, _einittext
1154  *
1155  * Pattern 5:
1156  *   GCC may optimize static inlines when fed constant arg(s) resulting
1157  *   in functions like cpumask_empty() -- generating an associated symbol
1158  *   cpumask_empty.constprop.3 that appears in the audit.  If the const that
1159  *   is passed in comes from __init, like say nmi_ipi_mask, we get a
1160  *   meaningless section warning.  May need to add isra symbols too...
1161  *   This pattern is identified by
1162  *   tosec   = init section
1163  *   fromsec = text section
1164  *   refsymname = *.constprop.*
1165  *
1166  * Pattern 6:
1167  *   Hide section mismatch warnings for ELF local symbols.  The goal
1168  *   is to eliminate false positive modpost warnings caused by
1169  *   compiler-generated ELF local symbol names such as ".LANCHOR1".
1170  *   Autogenerated symbol names bypass modpost's "Pattern 2"
1171  *   whitelisting, which relies on pattern-matching against symbol
1172  *   names to work.  (One situation where gcc can autogenerate ELF
1173  *   local symbols is when "-fsection-anchors" is used.)
1174  **/
1175 static int secref_whitelist(const struct sectioncheck *mismatch,
1176                             const char *fromsec, const char *fromsym,
1177                             const char *tosec, const char *tosym)
1178 {
1179         /* Check for pattern 1 */
1180         if (match(tosec, init_data_sections) &&
1181             match(fromsec, data_sections) &&
1182             strstarts(fromsym, "__param"))
1183                 return 0;
1184
1185         /* Check for pattern 1a */
1186         if (strcmp(tosec, ".init.text") == 0 &&
1187             match(fromsec, data_sections) &&
1188             strstarts(fromsym, "__param_ops_"))
1189                 return 0;
1190
1191         /* Check for pattern 2 */
1192         if (match(tosec, init_exit_sections) &&
1193             match(fromsec, data_sections) &&
1194             match(fromsym, mismatch->symbol_white_list))
1195                 return 0;
1196
1197         /* Check for pattern 3 */
1198         if (match(fromsec, head_sections) &&
1199             match(tosec, init_sections))
1200                 return 0;
1201
1202         /* Check for pattern 4 */
1203         if (match(tosym, linker_symbols))
1204                 return 0;
1205
1206         /* Check for pattern 5 */
1207         if (match(fromsec, text_sections) &&
1208             match(tosec, init_sections) &&
1209             match(fromsym, optim_symbols))
1210                 return 0;
1211
1212         /* Check for pattern 6 */
1213         if (strstarts(fromsym, ".L"))
1214                 return 0;
1215
1216         return 1;
1217 }
1218
1219 static inline int is_arm_mapping_symbol(const char *str)
1220 {
1221         return str[0] == '$' && strchr("axtd", str[1])
1222                && (str[2] == '\0' || str[2] == '.');
1223 }
1224
1225 /*
1226  * If there's no name there, ignore it; likewise, ignore it if it's
1227  * one of the magic symbols emitted used by current ARM tools.
1228  *
1229  * Otherwise if find_symbols_between() returns those symbols, they'll
1230  * fail the whitelist tests and cause lots of false alarms ... fixable
1231  * only by merging __exit and __init sections into __text, bloating
1232  * the kernel (which is especially evil on embedded platforms).
1233  */
1234 static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
1235 {
1236         const char *name = elf->strtab + sym->st_name;
1237
1238         if (!name || !strlen(name))
1239                 return 0;
1240         return !is_arm_mapping_symbol(name);
1241 }
1242
1243 /**
1244  * Find symbol based on relocation record info.
1245  * In some cases the symbol supplied is a valid symbol so
1246  * return refsym. If st_name != 0 we assume this is a valid symbol.
1247  * In other cases the symbol needs to be looked up in the symbol table
1248  * based on section and address.
1249  *  **/
1250 static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf64_Sword addr,
1251                                 Elf_Sym *relsym)
1252 {
1253         Elf_Sym *sym;
1254         Elf_Sym *near = NULL;
1255         Elf64_Sword distance = 20;
1256         Elf64_Sword d;
1257         unsigned int relsym_secindex;
1258
1259         if (relsym->st_name != 0)
1260                 return relsym;
1261
1262         relsym_secindex = get_secindex(elf, relsym);
1263         for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1264                 if (get_secindex(elf, sym) != relsym_secindex)
1265                         continue;
1266                 if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)
1267                         continue;
1268                 if (!is_valid_name(elf, sym))
1269                         continue;
1270                 if (sym->st_value == addr)
1271                         return sym;
1272                 /* Find a symbol nearby - addr are maybe negative */
1273                 d = sym->st_value - addr;
1274                 if (d < 0)
1275                         d = addr - sym->st_value;
1276                 if (d < distance) {
1277                         distance = d;
1278                         near = sym;
1279                 }
1280         }
1281         /* We need a close match */
1282         if (distance < 20)
1283                 return near;
1284         else
1285                 return NULL;
1286 }
1287
1288 /*
1289  * Find symbols before or equal addr and after addr - in the section sec.
1290  * If we find two symbols with equal offset prefer one with a valid name.
1291  * The ELF format may have a better way to detect what type of symbol
1292  * it is, but this works for now.
1293  **/
1294 static Elf_Sym *find_elf_symbol2(struct elf_info *elf, Elf_Addr addr,
1295                                  const char *sec)
1296 {
1297         Elf_Sym *sym;
1298         Elf_Sym *near = NULL;
1299         Elf_Addr distance = ~0;
1300
1301         for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {
1302                 const char *symsec;
1303
1304                 if (is_shndx_special(sym->st_shndx))
1305                         continue;
1306                 symsec = sec_name(elf, get_secindex(elf, sym));
1307                 if (strcmp(symsec, sec) != 0)
1308                         continue;
1309                 if (!is_valid_name(elf, sym))
1310                         continue;
1311                 if (sym->st_value <= addr) {
1312                         if ((addr - sym->st_value) < distance) {
1313                                 distance = addr - sym->st_value;
1314                                 near = sym;
1315                         } else if ((addr - sym->st_value) == distance) {
1316                                 near = sym;
1317                         }
1318                 }
1319         }
1320         return near;
1321 }
1322
1323 /*
1324  * Convert a section name to the function/data attribute
1325  * .init.text => __init
1326  * .memexitconst => __memconst
1327  * etc.
1328  *
1329  * The memory of returned value has been allocated on a heap. The user of this
1330  * method should free it after usage.
1331 */
1332 static char *sec2annotation(const char *s)
1333 {
1334         if (match(s, init_exit_sections)) {
1335                 char *p = NOFAIL(malloc(20));
1336                 char *r = p;
1337
1338                 *p++ = '_';
1339                 *p++ = '_';
1340                 if (*s == '.')
1341                         s++;
1342                 while (*s && *s != '.')
1343                         *p++ = *s++;
1344                 *p = '\0';
1345                 if (*s == '.')
1346                         s++;
1347                 if (strstr(s, "rodata") != NULL)
1348                         strcat(p, "const ");
1349                 else if (strstr(s, "data") != NULL)
1350                         strcat(p, "data ");
1351                 else
1352                         strcat(p, " ");
1353                 return r;
1354         } else {
1355                 return NOFAIL(strdup(""));
1356         }
1357 }
1358
1359 static int is_function(Elf_Sym *sym)
1360 {
1361         if (sym)
1362                 return ELF_ST_TYPE(sym->st_info) == STT_FUNC;
1363         else
1364                 return -1;
1365 }
1366
1367 static void print_section_list(const char * const list[20])
1368 {
1369         const char *const *s = list;
1370
1371         while (*s) {
1372                 fprintf(stderr, "%s", *s);
1373                 s++;
1374                 if (*s)
1375                         fprintf(stderr, ", ");
1376         }
1377         fprintf(stderr, "\n");
1378 }
1379
1380 static inline void get_pretty_name(int is_func, const char** name, const char** name_p)
1381 {
1382         switch (is_func) {
1383         case 0: *name = "variable"; *name_p = ""; break;
1384         case 1: *name = "function"; *name_p = "()"; break;
1385         default: *name = "(unknown reference)"; *name_p = ""; break;
1386         }
1387 }
1388
1389 /*
1390  * Print a warning about a section mismatch.
1391  * Try to find symbols near it so user can find it.
1392  * Check whitelist before warning - it may be a false positive.
1393  */
1394 static void report_sec_mismatch(const char *modname,
1395                                 const struct sectioncheck *mismatch,
1396                                 const char *fromsec,
1397                                 unsigned long long fromaddr,
1398                                 const char *fromsym,
1399                                 int from_is_func,
1400                                 const char *tosec, const char *tosym,
1401                                 int to_is_func)
1402 {
1403         const char *from, *from_p;
1404         const char *to, *to_p;
1405         char *prl_from;
1406         char *prl_to;
1407
1408         sec_mismatch_count++;
1409         if (!sec_mismatch_verbose)
1410                 return;
1411
1412         get_pretty_name(from_is_func, &from, &from_p);
1413         get_pretty_name(to_is_func, &to, &to_p);
1414
1415         warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s "
1416              "to the %s %s:%s%s\n",
1417              modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec,
1418              tosym, to_p);
1419
1420         switch (mismatch->mismatch) {
1421         case TEXT_TO_ANY_INIT:
1422                 prl_from = sec2annotation(fromsec);
1423                 prl_to = sec2annotation(tosec);
1424                 fprintf(stderr,
1425                 "The function %s%s() references\n"
1426                 "the %s %s%s%s.\n"
1427                 "This is often because %s lacks a %s\n"
1428                 "annotation or the annotation of %s is wrong.\n",
1429                 prl_from, fromsym,
1430                 to, prl_to, tosym, to_p,
1431                 fromsym, prl_to, tosym);
1432                 free(prl_from);
1433                 free(prl_to);
1434                 break;
1435         case DATA_TO_ANY_INIT: {
1436                 prl_to = sec2annotation(tosec);
1437                 fprintf(stderr,
1438                 "The variable %s references\n"
1439                 "the %s %s%s%s\n"
1440                 "If the reference is valid then annotate the\n"
1441                 "variable with __init* or __refdata (see linux/init.h) "
1442                 "or name the variable:\n",
1443                 fromsym, to, prl_to, tosym, to_p);
1444                 print_section_list(mismatch->symbol_white_list);
1445                 free(prl_to);
1446                 break;
1447         }
1448         case TEXT_TO_ANY_EXIT:
1449                 prl_to = sec2annotation(tosec);
1450                 fprintf(stderr,
1451                 "The function %s() references a %s in an exit section.\n"
1452                 "Often the %s %s%s has valid usage outside the exit section\n"
1453                 "and the fix is to remove the %sannotation of %s.\n",
1454                 fromsym, to, to, tosym, to_p, prl_to, tosym);
1455                 free(prl_to);
1456                 break;
1457         case DATA_TO_ANY_EXIT: {
1458                 prl_to = sec2annotation(tosec);
1459                 fprintf(stderr,
1460                 "The variable %s references\n"
1461                 "the %s %s%s%s\n"
1462                 "If the reference is valid then annotate the\n"
1463                 "variable with __exit* (see linux/init.h) or "
1464                 "name the variable:\n",
1465                 fromsym, to, prl_to, tosym, to_p);
1466                 print_section_list(mismatch->symbol_white_list);
1467                 free(prl_to);
1468                 break;
1469         }
1470         case XXXINIT_TO_SOME_INIT:
1471         case XXXEXIT_TO_SOME_EXIT:
1472                 prl_from = sec2annotation(fromsec);
1473                 prl_to = sec2annotation(tosec);
1474                 fprintf(stderr,
1475                 "The %s %s%s%s references\n"
1476                 "a %s %s%s%s.\n"
1477                 "If %s is only used by %s then\n"
1478                 "annotate %s with a matching annotation.\n",
1479                 from, prl_from, fromsym, from_p,
1480                 to, prl_to, tosym, to_p,
1481                 tosym, fromsym, tosym);
1482                 free(prl_from);
1483                 free(prl_to);
1484                 break;
1485         case ANY_INIT_TO_ANY_EXIT:
1486                 prl_from = sec2annotation(fromsec);
1487                 prl_to = sec2annotation(tosec);
1488                 fprintf(stderr,
1489                 "The %s %s%s%s references\n"
1490                 "a %s %s%s%s.\n"
1491                 "This is often seen when error handling "
1492                 "in the init function\n"
1493                 "uses functionality in the exit path.\n"
1494                 "The fix is often to remove the %sannotation of\n"
1495                 "%s%s so it may be used outside an exit section.\n",
1496                 from, prl_from, fromsym, from_p,
1497                 to, prl_to, tosym, to_p,
1498                 prl_to, tosym, to_p);
1499                 free(prl_from);
1500                 free(prl_to);
1501                 break;
1502         case ANY_EXIT_TO_ANY_INIT:
1503                 prl_from = sec2annotation(fromsec);
1504                 prl_to = sec2annotation(tosec);
1505                 fprintf(stderr,
1506                 "The %s %s%s%s references\n"
1507                 "a %s %s%s%s.\n"
1508                 "This is often seen when error handling "
1509                 "in the exit function\n"
1510                 "uses functionality in the init path.\n"
1511                 "The fix is often to remove the %sannotation of\n"
1512                 "%s%s so it may be used outside an init section.\n",
1513                 from, prl_from, fromsym, from_p,
1514                 to, prl_to, tosym, to_p,
1515                 prl_to, tosym, to_p);
1516                 free(prl_from);
1517                 free(prl_to);
1518                 break;
1519         case EXPORT_TO_INIT_EXIT:
1520                 prl_to = sec2annotation(tosec);
1521                 fprintf(stderr,
1522                 "The symbol %s is exported and annotated %s\n"
1523                 "Fix this by removing the %sannotation of %s "
1524                 "or drop the export.\n",
1525                 tosym, prl_to, prl_to, tosym);
1526                 free(prl_to);
1527                 break;
1528         case EXTABLE_TO_NON_TEXT:
1529                 fatal("There's a special handler for this mismatch type, "
1530                       "we should never get here.");
1531                 break;
1532         }
1533         fprintf(stderr, "\n");
1534 }
1535
1536 static void default_mismatch_handler(const char *modname, struct elf_info *elf,
1537                                      const struct sectioncheck* const mismatch,
1538                                      Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1539 {
1540         const char *tosec;
1541         Elf_Sym *to;
1542         Elf_Sym *from;
1543         const char *tosym;
1544         const char *fromsym;
1545
1546         from = find_elf_symbol2(elf, r->r_offset, fromsec);
1547         fromsym = sym_name(elf, from);
1548
1549         if (strstarts(fromsym, "reference___initcall"))
1550                 return;
1551
1552         tosec = sec_name(elf, get_secindex(elf, sym));
1553         to = find_elf_symbol(elf, r->r_addend, sym);
1554         tosym = sym_name(elf, to);
1555
1556         /* check whitelist - we may ignore it */
1557         if (secref_whitelist(mismatch,
1558                              fromsec, fromsym, tosec, tosym)) {
1559                 report_sec_mismatch(modname, mismatch,
1560                                     fromsec, r->r_offset, fromsym,
1561                                     is_function(from), tosec, tosym,
1562                                     is_function(to));
1563         }
1564 }
1565
1566 static int is_executable_section(struct elf_info* elf, unsigned int section_index)
1567 {
1568         if (section_index > elf->num_sections)
1569                 fatal("section_index is outside elf->num_sections!\n");
1570
1571         return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR);
1572 }
1573
1574 /*
1575  * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size()
1576  * to know the sizeof(struct exception_table_entry) for the target architecture.
1577  */
1578 static unsigned int extable_entry_size = 0;
1579 static void find_extable_entry_size(const char* const sec, const Elf_Rela* r)
1580 {
1581         /*
1582          * If we're currently checking the second relocation within __ex_table,
1583          * that relocation offset tells us the offsetof(struct
1584          * exception_table_entry, fixup) which is equal to sizeof(struct
1585          * exception_table_entry) divided by two.  We use that to our advantage
1586          * since there's no portable way to get that size as every architecture
1587          * seems to go with different sized types.  Not pretty but better than
1588          * hard-coding the size for every architecture..
1589          */
1590         if (!extable_entry_size)
1591                 extable_entry_size = r->r_offset * 2;
1592 }
1593
1594 static inline bool is_extable_fault_address(Elf_Rela *r)
1595 {
1596         /*
1597          * extable_entry_size is only discovered after we've handled the
1598          * _second_ relocation in __ex_table, so only abort when we're not
1599          * handling the first reloc and extable_entry_size is zero.
1600          */
1601         if (r->r_offset && extable_entry_size == 0)
1602                 fatal("extable_entry size hasn't been discovered!\n");
1603
1604         return ((r->r_offset == 0) ||
1605                 (r->r_offset % extable_entry_size == 0));
1606 }
1607
1608 #define is_second_extable_reloc(Start, Cur, Sec)                        \
1609         (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0))
1610
1611 static void report_extable_warnings(const char* modname, struct elf_info* elf,
1612                                     const struct sectioncheck* const mismatch,
1613                                     Elf_Rela* r, Elf_Sym* sym,
1614                                     const char* fromsec, const char* tosec)
1615 {
1616         Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec);
1617         const char* fromsym_name = sym_name(elf, fromsym);
1618         Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym);
1619         const char* tosym_name = sym_name(elf, tosym);
1620         const char* from_pretty_name;
1621         const char* from_pretty_name_p;
1622         const char* to_pretty_name;
1623         const char* to_pretty_name_p;
1624
1625         get_pretty_name(is_function(fromsym),
1626                         &from_pretty_name, &from_pretty_name_p);
1627         get_pretty_name(is_function(tosym),
1628                         &to_pretty_name, &to_pretty_name_p);
1629
1630         warn("%s(%s+0x%lx): Section mismatch in reference"
1631              " from the %s %s%s to the %s %s:%s%s\n",
1632              modname, fromsec, (long)r->r_offset, from_pretty_name,
1633              fromsym_name, from_pretty_name_p,
1634              to_pretty_name, tosec, tosym_name, to_pretty_name_p);
1635
1636         if (!match(tosec, mismatch->bad_tosec) &&
1637             is_executable_section(elf, get_secindex(elf, sym)))
1638                 fprintf(stderr,
1639                         "The relocation at %s+0x%lx references\n"
1640                         "section \"%s\" which is not in the list of\n"
1641                         "authorized sections.  If you're adding a new section\n"
1642                         "and/or if this reference is valid, add \"%s\" to the\n"
1643                         "list of authorized sections to jump to on fault.\n"
1644                         "This can be achieved by adding \"%s\" to \n"
1645                         "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n",
1646                         fromsec, (long)r->r_offset, tosec, tosec, tosec);
1647 }
1648
1649 static void extable_mismatch_handler(const char* modname, struct elf_info *elf,
1650                                      const struct sectioncheck* const mismatch,
1651                                      Elf_Rela* r, Elf_Sym* sym,
1652                                      const char *fromsec)
1653 {
1654         const char* tosec = sec_name(elf, get_secindex(elf, sym));
1655
1656         sec_mismatch_count++;
1657
1658         if (sec_mismatch_verbose)
1659                 report_extable_warnings(modname, elf, mismatch, r, sym,
1660                                         fromsec, tosec);
1661
1662         if (match(tosec, mismatch->bad_tosec))
1663                 fatal("The relocation at %s+0x%lx references\n"
1664                       "section \"%s\" which is black-listed.\n"
1665                       "Something is seriously wrong and should be fixed.\n"
1666                       "You might get more information about where this is\n"
1667                       "coming from by using scripts/check_extable.sh %s\n",
1668                       fromsec, (long)r->r_offset, tosec, modname);
1669         else if (!is_executable_section(elf, get_secindex(elf, sym))) {
1670                 if (is_extable_fault_address(r))
1671                         fatal("The relocation at %s+0x%lx references\n"
1672                               "section \"%s\" which is not executable, IOW\n"
1673                               "it is not possible for the kernel to fault\n"
1674                               "at that address.  Something is seriously wrong\n"
1675                               "and should be fixed.\n",
1676                               fromsec, (long)r->r_offset, tosec);
1677                 else
1678                         fatal("The relocation at %s+0x%lx references\n"
1679                               "section \"%s\" which is not executable, IOW\n"
1680                               "the kernel will fault if it ever tries to\n"
1681                               "jump to it.  Something is seriously wrong\n"
1682                               "and should be fixed.\n",
1683                               fromsec, (long)r->r_offset, tosec);
1684         }
1685 }
1686
1687 static void check_section_mismatch(const char *modname, struct elf_info *elf,
1688                                    Elf_Rela *r, Elf_Sym *sym, const char *fromsec)
1689 {
1690         const char *tosec = sec_name(elf, get_secindex(elf, sym));
1691         const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec);
1692
1693         if (mismatch) {
1694                 if (mismatch->handler)
1695                         mismatch->handler(modname, elf,  mismatch,
1696                                           r, sym, fromsec);
1697                 else
1698                         default_mismatch_handler(modname, elf, mismatch,
1699                                                  r, sym, fromsec);
1700         }
1701 }
1702
1703 static unsigned int *reloc_location(struct elf_info *elf,
1704                                     Elf_Shdr *sechdr, Elf_Rela *r)
1705 {
1706         Elf_Shdr *sechdrs = elf->sechdrs;
1707         int section = sechdr->sh_info;
1708
1709         return (void *)elf->hdr + sechdrs[section].sh_offset +
1710                 r->r_offset;
1711 }
1712
1713 static int addend_386_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1714 {
1715         unsigned int r_typ = ELF_R_TYPE(r->r_info);
1716         unsigned int *location = reloc_location(elf, sechdr, r);
1717
1718         switch (r_typ) {
1719         case R_386_32:
1720                 r->r_addend = TO_NATIVE(*location);
1721                 break;
1722         case R_386_PC32:
1723                 r->r_addend = TO_NATIVE(*location) + 4;
1724                 /* For CONFIG_RELOCATABLE=y */
1725                 if (elf->hdr->e_type == ET_EXEC)
1726                         r->r_addend += r->r_offset;
1727                 break;
1728         }
1729         return 0;
1730 }
1731
1732 #ifndef R_ARM_CALL
1733 #define R_ARM_CALL      28
1734 #endif
1735 #ifndef R_ARM_JUMP24
1736 #define R_ARM_JUMP24    29
1737 #endif
1738
1739 #ifndef R_ARM_THM_CALL
1740 #define R_ARM_THM_CALL          10
1741 #endif
1742 #ifndef R_ARM_THM_JUMP24
1743 #define R_ARM_THM_JUMP24        30
1744 #endif
1745 #ifndef R_ARM_THM_JUMP19
1746 #define R_ARM_THM_JUMP19        51
1747 #endif
1748
1749 static int addend_arm_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1750 {
1751         unsigned int r_typ = ELF_R_TYPE(r->r_info);
1752
1753         switch (r_typ) {
1754         case R_ARM_ABS32:
1755                 /* From ARM ABI: (S + A) | T */
1756                 r->r_addend = (int)(long)
1757                               (elf->symtab_start + ELF_R_SYM(r->r_info));
1758                 break;
1759         case R_ARM_PC24:
1760         case R_ARM_CALL:
1761         case R_ARM_JUMP24:
1762         case R_ARM_THM_CALL:
1763         case R_ARM_THM_JUMP24:
1764         case R_ARM_THM_JUMP19:
1765                 /* From ARM ABI: ((S + A) | T) - P */
1766                 r->r_addend = (int)(long)(elf->hdr +
1767                               sechdr->sh_offset +
1768                               (r->r_offset - sechdr->sh_addr));
1769                 break;
1770         default:
1771                 return 1;
1772         }
1773         return 0;
1774 }
1775
1776 static int addend_mips_rel(struct elf_info *elf, Elf_Shdr *sechdr, Elf_Rela *r)
1777 {
1778         unsigned int r_typ = ELF_R_TYPE(r->r_info);
1779         unsigned int *location = reloc_location(elf, sechdr, r);
1780         unsigned int inst;
1781
1782         if (r_typ == R_MIPS_HI16)
1783                 return 1;       /* skip this */
1784         inst = TO_NATIVE(*location);
1785         switch (r_typ) {
1786         case R_MIPS_LO16:
1787                 r->r_addend = inst & 0xffff;
1788                 break;
1789         case R_MIPS_26:
1790                 r->r_addend = (inst & 0x03ffffff) << 2;
1791                 break;
1792         case R_MIPS_32:
1793                 r->r_addend = inst;
1794                 break;
1795         }
1796         return 0;
1797 }
1798
1799 static void section_rela(const char *modname, struct elf_info *elf,
1800                          Elf_Shdr *sechdr)
1801 {
1802         Elf_Sym  *sym;
1803         Elf_Rela *rela;
1804         Elf_Rela r;
1805         unsigned int r_sym;
1806         const char *fromsec;
1807
1808         Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset;
1809         Elf_Rela *stop  = (void *)start + sechdr->sh_size;
1810
1811         fromsec = sech_name(elf, sechdr);
1812         fromsec += strlen(".rela");
1813         /* if from section (name) is know good then skip it */
1814         if (match(fromsec, section_white_list))
1815                 return;
1816
1817         for (rela = start; rela < stop; rela++) {
1818                 r.r_offset = TO_NATIVE(rela->r_offset);
1819 #if KERNEL_ELFCLASS == ELFCLASS64
1820                 if (elf->hdr->e_machine == EM_MIPS) {
1821                         unsigned int r_typ;
1822                         r_sym = ELF64_MIPS_R_SYM(rela->r_info);
1823                         r_sym = TO_NATIVE(r_sym);
1824                         r_typ = ELF64_MIPS_R_TYPE(rela->r_info);
1825                         r.r_info = ELF64_R_INFO(r_sym, r_typ);
1826                 } else {
1827                         r.r_info = TO_NATIVE(rela->r_info);
1828                         r_sym = ELF_R_SYM(r.r_info);
1829                 }
1830 #else
1831                 r.r_info = TO_NATIVE(rela->r_info);
1832                 r_sym = ELF_R_SYM(r.r_info);
1833 #endif
1834                 r.r_addend = TO_NATIVE(rela->r_addend);
1835                 sym = elf->symtab_start + r_sym;
1836                 /* Skip special sections */
1837                 if (is_shndx_special(sym->st_shndx))
1838                         continue;
1839                 if (is_second_extable_reloc(start, rela, fromsec))
1840                         find_extable_entry_size(fromsec, &r);
1841                 check_section_mismatch(modname, elf, &r, sym, fromsec);
1842         }
1843 }
1844
1845 static void section_rel(const char *modname, struct elf_info *elf,
1846                         Elf_Shdr *sechdr)
1847 {
1848         Elf_Sym *sym;
1849         Elf_Rel *rel;
1850         Elf_Rela r;
1851         unsigned int r_sym;
1852         const char *fromsec;
1853
1854         Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset;
1855         Elf_Rel *stop  = (void *)start + sechdr->sh_size;
1856
1857         fromsec = sech_name(elf, sechdr);
1858         fromsec += strlen(".rel");
1859         /* if from section (name) is know good then skip it */
1860         if (match(fromsec, section_white_list))
1861                 return;
1862
1863         for (rel = start; rel < stop; rel++) {
1864                 r.r_offset = TO_NATIVE(rel->r_offset);
1865 #if KERNEL_ELFCLASS == ELFCLASS64
1866                 if (elf->hdr->e_machine == EM_MIPS) {
1867                         unsigned int r_typ;
1868                         r_sym = ELF64_MIPS_R_SYM(rel->r_info);
1869                         r_sym = TO_NATIVE(r_sym);
1870                         r_typ = ELF64_MIPS_R_TYPE(rel->r_info);
1871                         r.r_info = ELF64_R_INFO(r_sym, r_typ);
1872                 } else {
1873                         r.r_info = TO_NATIVE(rel->r_info);
1874                         r_sym = ELF_R_SYM(r.r_info);
1875                 }
1876 #else
1877                 r.r_info = TO_NATIVE(rel->r_info);
1878                 r_sym = ELF_R_SYM(r.r_info);
1879 #endif
1880                 r.r_addend = 0;
1881                 switch (elf->hdr->e_machine) {
1882                 case EM_386:
1883                         if (addend_386_rel(elf, sechdr, &r))
1884                                 continue;
1885                         break;
1886                 case EM_ARM:
1887                         if (addend_arm_rel(elf, sechdr, &r))
1888                                 continue;
1889                         break;
1890                 case EM_MIPS:
1891                         if (addend_mips_rel(elf, sechdr, &r))
1892                                 continue;
1893                         break;
1894                 }
1895                 sym = elf->symtab_start + r_sym;
1896                 /* Skip special sections */
1897                 if (is_shndx_special(sym->st_shndx))
1898                         continue;
1899                 if (is_second_extable_reloc(start, rel, fromsec))
1900                         find_extable_entry_size(fromsec, &r);
1901                 check_section_mismatch(modname, elf, &r, sym, fromsec);
1902         }
1903 }
1904
1905 /**
1906  * A module includes a number of sections that are discarded
1907  * either when loaded or when used as built-in.
1908  * For loaded modules all functions marked __init and all data
1909  * marked __initdata will be discarded when the module has been initialized.
1910  * Likewise for modules used built-in the sections marked __exit
1911  * are discarded because __exit marked function are supposed to be called
1912  * only when a module is unloaded which never happens for built-in modules.
1913  * The check_sec_ref() function traverses all relocation records
1914  * to find all references to a section that reference a section that will
1915  * be discarded and warns about it.
1916  **/
1917 static void check_sec_ref(struct module *mod, const char *modname,
1918                           struct elf_info *elf)
1919 {
1920         int i;
1921         Elf_Shdr *sechdrs = elf->sechdrs;
1922
1923         /* Walk through all sections */
1924         for (i = 0; i < elf->num_sections; i++) {
1925                 check_section(modname, elf, &elf->sechdrs[i]);
1926                 /* We want to process only relocation sections and not .init */
1927                 if (sechdrs[i].sh_type == SHT_RELA)
1928                         section_rela(modname, elf, &elf->sechdrs[i]);
1929                 else if (sechdrs[i].sh_type == SHT_REL)
1930                         section_rel(modname, elf, &elf->sechdrs[i]);
1931         }
1932 }
1933
1934 static char *remove_dot(char *s)
1935 {
1936         size_t n = strcspn(s, ".");
1937
1938         if (n && s[n]) {
1939                 size_t m = strspn(s + n + 1, "0123456789");
1940                 if (m && (s[n + m] == '.' || s[n + m] == 0))
1941                         s[n] = 0;
1942         }
1943         return s;
1944 }
1945
1946 static void read_symbols(const char *modname)
1947 {
1948         const char *symname;
1949         char *version;
1950         char *license;
1951         struct module *mod;
1952         struct elf_info info = { };
1953         Elf_Sym *sym;
1954
1955         if (!parse_elf(&info, modname))
1956                 return;
1957
1958         mod = new_module(modname);
1959
1960         /* When there's no vmlinux, don't print warnings about
1961          * unresolved symbols (since there'll be too many ;) */
1962         if (is_vmlinux(modname)) {
1963                 have_vmlinux = 1;
1964                 mod->skip = 1;
1965         }
1966
1967         license = get_modinfo(&info, "license");
1968         if (!license && !is_vmlinux(modname))
1969                 warn("modpost: missing MODULE_LICENSE() in %s\n"
1970                      "see include/linux/module.h for "
1971                      "more information\n", modname);
1972         while (license) {
1973                 if (license_is_gpl_compatible(license))
1974                         mod->gpl_compatible = 1;
1975                 else {
1976                         mod->gpl_compatible = 0;
1977                         break;
1978                 }
1979                 license = get_next_modinfo(&info, "license", license);
1980         }
1981
1982         for (sym = info.symtab_start; sym < info.symtab_stop; sym++) {
1983                 symname = remove_dot(info.strtab + sym->st_name);
1984
1985                 handle_modversions(mod, &info, sym, symname);
1986                 handle_moddevtable(mod, &info, sym, symname);
1987         }
1988         if (!is_vmlinux(modname) || vmlinux_section_warnings)
1989                 check_sec_ref(mod, modname, &info);
1990
1991         version = get_modinfo(&info, "version");
1992         if (version)
1993                 maybe_frob_rcs_version(modname, version, info.modinfo,
1994                                        version - (char *)info.hdr);
1995         if (version || (all_versions && !is_vmlinux(modname)))
1996                 get_src_version(modname, mod->srcversion,
1997                                 sizeof(mod->srcversion)-1);
1998
1999         parse_elf_finish(&info);
2000
2001         /* Our trick to get versioning for module struct etc. - it's
2002          * never passed as an argument to an exported function, so
2003          * the automatic versioning doesn't pick it up, but it's really
2004          * important anyhow */
2005         if (modversions)
2006                 mod->unres = alloc_symbol("module_layout", 0, mod->unres);
2007 }
2008
2009 static void read_symbols_from_files(const char *filename)
2010 {
2011         FILE *in = stdin;
2012         char fname[PATH_MAX];
2013
2014         if (strcmp(filename, "-") != 0) {
2015                 in = fopen(filename, "r");
2016                 if (!in)
2017                         fatal("Can't open filenames file %s: %m", filename);
2018         }
2019
2020         while (fgets(fname, PATH_MAX, in) != NULL) {
2021                 if (strends(fname, "\n"))
2022                         fname[strlen(fname)-1] = '\0';
2023                 read_symbols(fname);
2024         }
2025
2026         if (in != stdin)
2027                 fclose(in);
2028 }
2029
2030 #define SZ 500
2031
2032 /* We first write the generated file into memory using the
2033  * following helper, then compare to the file on disk and
2034  * only update the later if anything changed */
2035
2036 void __attribute__((format(printf, 2, 3))) buf_printf(struct buffer *buf,
2037                                                       const char *fmt, ...)
2038 {
2039         char tmp[SZ];
2040         int len;
2041         va_list ap;
2042
2043         va_start(ap, fmt);
2044         len = vsnprintf(tmp, SZ, fmt, ap);
2045         buf_write(buf, tmp, len);
2046         va_end(ap);
2047 }
2048
2049 void buf_write(struct buffer *buf, const char *s, int len)
2050 {
2051         if (buf->size - buf->pos < len) {
2052                 buf->size += len + SZ;
2053                 buf->p = NOFAIL(realloc(buf->p, buf->size));
2054         }
2055         strncpy(buf->p + buf->pos, s, len);
2056         buf->pos += len;
2057 }
2058
2059 static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
2060 {
2061         const char *e = is_vmlinux(m) ?"":".ko";
2062
2063         switch (exp) {
2064         case export_gpl:
2065                 fatal("modpost: GPL-incompatible module %s%s "
2066                       "uses GPL-only symbol '%s'\n", m, e, s);
2067                 break;
2068         case export_unused_gpl:
2069                 fatal("modpost: GPL-incompatible module %s%s "
2070                       "uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
2071                 break;
2072         case export_gpl_future:
2073                 warn("modpost: GPL-incompatible module %s%s "
2074                       "uses future GPL-only symbol '%s'\n", m, e, s);
2075                 break;
2076         case export_plain:
2077         case export_unused:
2078         case export_unknown:
2079                 /* ignore */
2080                 break;
2081         }
2082 }
2083
2084 static void check_for_unused(enum export exp, const char *m, const char *s)
2085 {
2086         const char *e = is_vmlinux(m) ?"":".ko";
2087
2088         switch (exp) {
2089         case export_unused:
2090         case export_unused_gpl:
2091                 warn("modpost: module %s%s "
2092                       "uses symbol '%s' marked UNUSED\n", m, e, s);
2093                 break;
2094         default:
2095                 /* ignore */
2096                 break;
2097         }
2098 }
2099
2100 static void check_exports(struct module *mod)
2101 {
2102         struct symbol *s, *exp;
2103
2104         for (s = mod->unres; s; s = s->next) {
2105                 const char *basename;
2106                 exp = find_symbol(s->name);
2107                 if (!exp || exp->module == mod)
2108                         continue;
2109                 basename = strrchr(mod->name, '/');
2110                 if (basename)
2111                         basename++;
2112                 else
2113                         basename = mod->name;
2114                 if (!mod->gpl_compatible)
2115                         check_for_gpl_usage(exp->export, basename, exp->name);
2116                 check_for_unused(exp->export, basename, exp->name);
2117         }
2118 }
2119
2120 static int check_modname_len(struct module *mod)
2121 {
2122         const char *mod_name;
2123
2124         mod_name = strrchr(mod->name, '/');
2125         if (mod_name == NULL)
2126                 mod_name = mod->name;
2127         else
2128                 mod_name++;
2129         if (strlen(mod_name) >= MODULE_NAME_LEN) {
2130                 merror("module name is too long [%s.ko]\n", mod->name);
2131                 return 1;
2132         }
2133
2134         return 0;
2135 }
2136
2137 /**
2138  * Header for the generated file
2139  **/
2140 static void add_header(struct buffer *b, struct module *mod)
2141 {
2142         buf_printf(b, "#include <linux/build-salt.h>\n");
2143         buf_printf(b, "#include <linux/module.h>\n");
2144         buf_printf(b, "#include <linux/vermagic.h>\n");
2145         buf_printf(b, "#include <linux/compiler.h>\n");
2146         buf_printf(b, "\n");
2147         buf_printf(b, "BUILD_SALT;\n");
2148         buf_printf(b, "\n");
2149         buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
2150         buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
2151         buf_printf(b, "\n");
2152         buf_printf(b, "__visible struct module __this_module\n");
2153         buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
2154         buf_printf(b, "\t.name = KBUILD_MODNAME,\n");
2155         if (mod->has_init)
2156                 buf_printf(b, "\t.init = init_module,\n");
2157         if (mod->has_cleanup)
2158                 buf_printf(b, "#ifdef CONFIG_MODULE_UNLOAD\n"
2159                               "\t.exit = cleanup_module,\n"
2160                               "#endif\n");
2161         buf_printf(b, "\t.arch = MODULE_ARCH_INIT,\n");
2162         buf_printf(b, "};\n");
2163 }
2164
2165 static void add_intree_flag(struct buffer *b, int is_intree)
2166 {
2167         if (is_intree)
2168                 buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
2169 }
2170
2171 /* Cannot check for assembler */
2172 static void add_retpoline(struct buffer *b)
2173 {
2174         buf_printf(b, "\n#ifdef CONFIG_RETPOLINE\n");
2175         buf_printf(b, "MODULE_INFO(retpoline, \"Y\");\n");
2176         buf_printf(b, "#endif\n");
2177 }
2178
2179 static void add_staging_flag(struct buffer *b, const char *name)
2180 {
2181         if (strstarts(name, "drivers/staging"))
2182                 buf_printf(b, "\nMODULE_INFO(staging, \"Y\");\n");
2183 }
2184
2185 /**
2186  * Record CRCs for unresolved symbols
2187  **/
2188 static int add_versions(struct buffer *b, struct module *mod)
2189 {
2190         struct symbol *s, *exp;
2191         int err = 0;
2192
2193         for (s = mod->unres; s; s = s->next) {
2194                 exp = find_symbol(s->name);
2195                 if (!exp || exp->module == mod) {
2196                         if (have_vmlinux && !s->weak) {
2197                                 if (warn_unresolved) {
2198                                         warn("\"%s\" [%s.ko] undefined!\n",
2199                                              s->name, mod->name);
2200                                 } else {
2201                                         merror("\"%s\" [%s.ko] undefined!\n",
2202                                                s->name, mod->name);
2203                                         err = 1;
2204                                 }
2205                         }
2206                         continue;
2207                 }
2208                 s->module = exp->module;
2209                 s->crc_valid = exp->crc_valid;
2210                 s->crc = exp->crc;
2211         }
2212
2213         if (!modversions)
2214                 return err;
2215
2216         buf_printf(b, "\n");
2217         buf_printf(b, "static const struct modversion_info ____versions[]\n");
2218         buf_printf(b, "__used\n");
2219         buf_printf(b, "__attribute__((section(\"__versions\"))) = {\n");
2220
2221         for (s = mod->unres; s; s = s->next) {
2222                 if (!s->module)
2223                         continue;
2224                 if (!s->crc_valid) {
2225                         warn("\"%s\" [%s.ko] has no CRC!\n",
2226                                 s->name, mod->name);
2227                         continue;
2228                 }
2229                 if (strlen(s->name) >= MODULE_NAME_LEN) {
2230                         merror("too long symbol \"%s\" [%s.ko]\n",
2231                                s->name, mod->name);
2232                         err = 1;
2233                         break;
2234                 }
2235                 buf_printf(b, "\t{ %#8x, \"%s\" },\n",
2236                            s->crc, s->name);
2237         }
2238
2239         buf_printf(b, "};\n");
2240
2241         return err;
2242 }
2243
2244 static void add_depends(struct buffer *b, struct module *mod,
2245                         struct module *modules)
2246 {
2247         struct symbol *s;
2248         struct module *m;
2249         int first = 1;
2250
2251         for (m = modules; m; m = m->next)
2252                 m->seen = is_vmlinux(m->name);
2253
2254         buf_printf(b, "\n");
2255         buf_printf(b, "static const char __module_depends[]\n");
2256         buf_printf(b, "__used\n");
2257         buf_printf(b, "__attribute__((section(\".modinfo\"))) =\n");
2258         buf_printf(b, "\"depends=");
2259         for (s = mod->unres; s; s = s->next) {
2260                 const char *p;
2261                 if (!s->module)
2262                         continue;
2263
2264                 if (s->module->seen)
2265                         continue;
2266
2267                 s->module->seen = 1;
2268                 p = strrchr(s->module->name, '/');
2269                 if (p)
2270                         p++;
2271                 else
2272                         p = s->module->name;
2273                 buf_printf(b, "%s%s", first ? "" : ",", p);
2274                 first = 0;
2275         }
2276         buf_printf(b, "\";\n");
2277 }
2278
2279 static void add_srcversion(struct buffer *b, struct module *mod)
2280 {
2281         if (mod->srcversion[0]) {
2282                 buf_printf(b, "\n");
2283                 buf_printf(b, "MODULE_INFO(srcversion, \"%s\");\n",
2284                            mod->srcversion);
2285         }
2286 }
2287
2288 static void write_if_changed(struct buffer *b, const char *fname)
2289 {
2290         char *tmp;
2291         FILE *file;
2292         struct stat st;
2293
2294         file = fopen(fname, "r");
2295         if (!file)
2296                 goto write;
2297
2298         if (fstat(fileno(file), &st) < 0)
2299                 goto close_write;
2300
2301         if (st.st_size != b->pos)
2302                 goto close_write;
2303
2304         tmp = NOFAIL(malloc(b->pos));
2305         if (fread(tmp, 1, b->pos, file) != b->pos)
2306                 goto free_write;
2307
2308         if (memcmp(tmp, b->p, b->pos) != 0)
2309                 goto free_write;
2310
2311         free(tmp);
2312         fclose(file);
2313         return;
2314
2315  free_write:
2316         free(tmp);
2317  close_write:
2318         fclose(file);
2319  write:
2320         file = fopen(fname, "w");
2321         if (!file) {
2322                 perror(fname);
2323                 exit(1);
2324         }
2325         if (fwrite(b->p, 1, b->pos, file) != b->pos) {
2326                 perror(fname);
2327                 exit(1);
2328         }
2329         fclose(file);
2330 }
2331
2332 /* parse Module.symvers file. line format:
2333  * 0x12345678<tab>symbol<tab>module[[<tab>export]<tab>something]
2334  **/
2335 static void read_dump(const char *fname, unsigned int kernel)
2336 {
2337         unsigned long size, pos = 0;
2338         void *file = grab_file(fname, &size);
2339         char *line;
2340
2341         if (!file)
2342                 /* No symbol versions, silently ignore */
2343                 return;
2344
2345         while ((line = get_next_line(&pos, file, size))) {
2346                 char *symname, *modname, *d, *export, *end;
2347                 unsigned int crc;
2348                 struct module *mod;
2349                 struct symbol *s;
2350
2351                 if (!(symname = strchr(line, '\t')))
2352                         goto fail;
2353                 *symname++ = '\0';
2354                 if (!(modname = strchr(symname, '\t')))
2355                         goto fail;
2356                 *modname++ = '\0';
2357                 if ((export = strchr(modname, '\t')) != NULL)
2358                         *export++ = '\0';
2359                 if (export && ((end = strchr(export, '\t')) != NULL))
2360                         *end = '\0';
2361                 crc = strtoul(line, &d, 16);
2362                 if (*symname == '\0' || *modname == '\0' || *d != '\0')
2363                         goto fail;
2364                 mod = find_module(modname);
2365                 if (!mod) {
2366                         if (is_vmlinux(modname))
2367                                 have_vmlinux = 1;
2368                         mod = new_module(modname);
2369                         mod->skip = 1;
2370                 }
2371                 s = sym_add_exported(symname, mod, export_no(export));
2372                 s->kernel    = kernel;
2373                 s->preloaded = 1;
2374                 sym_update_crc(symname, mod, crc, export_no(export));
2375         }
2376         release_file(file, size);
2377         return;
2378 fail:
2379         release_file(file, size);
2380         fatal("parse error in symbol dump file\n");
2381 }
2382
2383 /* For normal builds always dump all symbols.
2384  * For external modules only dump symbols
2385  * that are not read from kernel Module.symvers.
2386  **/
2387 static int dump_sym(struct symbol *sym)
2388 {
2389         if (!external_module)
2390                 return 1;
2391         if (sym->vmlinux || sym->kernel)
2392                 return 0;
2393         return 1;
2394 }
2395
2396 static void write_dump(const char *fname)
2397 {
2398         struct buffer buf = { };
2399         struct symbol *symbol;
2400         int n;
2401
2402         for (n = 0; n < SYMBOL_HASH_SIZE ; n++) {
2403                 symbol = symbolhash[n];
2404                 while (symbol) {
2405                         if (dump_sym(symbol))
2406                                 buf_printf(&buf, "0x%08x\t%s\t%s\t%s\n",
2407                                         symbol->crc, symbol->name,
2408                                         symbol->module->name,
2409                                         export_str(symbol->export));
2410                         symbol = symbol->next;
2411                 }
2412         }
2413         write_if_changed(&buf, fname);
2414         free(buf.p);
2415 }
2416
2417 struct ext_sym_list {
2418         struct ext_sym_list *next;
2419         const char *file;
2420 };
2421
2422 int main(int argc, char **argv)
2423 {
2424         struct module *mod;
2425         struct buffer buf = { };
2426         char *kernel_read = NULL, *module_read = NULL;
2427         char *dump_write = NULL, *files_source = NULL;
2428         int opt;
2429         int err;
2430         struct ext_sym_list *extsym_iter;
2431         struct ext_sym_list *extsym_start = NULL;
2432
2433         while ((opt = getopt(argc, argv, "i:I:e:mnsST:o:awM:K:E")) != -1) {
2434                 switch (opt) {
2435                 case 'i':
2436                         kernel_read = optarg;
2437                         break;
2438                 case 'I':
2439                         module_read = optarg;
2440                         external_module = 1;
2441                         break;
2442                 case 'e':
2443                         external_module = 1;
2444                         extsym_iter =
2445                            NOFAIL(malloc(sizeof(*extsym_iter)));
2446                         extsym_iter->next = extsym_start;
2447                         extsym_iter->file = optarg;
2448                         extsym_start = extsym_iter;
2449                         break;
2450                 case 'm':
2451                         modversions = 1;
2452                         break;
2453                 case 'n':
2454                         ignore_missing_files = 1;
2455                         break;
2456                 case 'o':
2457                         dump_write = optarg;
2458                         break;
2459                 case 'a':
2460                         all_versions = 1;
2461                         break;
2462                 case 's':
2463                         vmlinux_section_warnings = 0;
2464                         break;
2465                 case 'S':
2466                         sec_mismatch_verbose = 0;
2467                         break;
2468                 case 'T':
2469                         files_source = optarg;
2470                         break;
2471                 case 'w':
2472                         warn_unresolved = 1;
2473                         break;
2474                 case 'E':
2475                         sec_mismatch_fatal = 1;
2476                         break;
2477                 default:
2478                         exit(1);
2479                 }
2480         }
2481
2482         if (kernel_read)
2483                 read_dump(kernel_read, 1);
2484         if (module_read)
2485                 read_dump(module_read, 0);
2486         while (extsym_start) {
2487                 read_dump(extsym_start->file, 0);
2488                 extsym_iter = extsym_start->next;
2489                 free(extsym_start);
2490                 extsym_start = extsym_iter;
2491         }
2492
2493         while (optind < argc)
2494                 read_symbols(argv[optind++]);
2495
2496         if (files_source)
2497                 read_symbols_from_files(files_source);
2498
2499         for (mod = modules; mod; mod = mod->next) {
2500                 if (mod->skip)
2501                         continue;
2502                 check_exports(mod);
2503         }
2504
2505         err = 0;
2506
2507         for (mod = modules; mod; mod = mod->next) {
2508                 char fname[PATH_MAX];
2509
2510                 if (mod->skip)
2511                         continue;
2512
2513                 buf.pos = 0;
2514
2515                 err |= check_modname_len(mod);
2516                 add_header(&buf, mod);
2517                 add_intree_flag(&buf, !external_module);
2518                 add_retpoline(&buf);
2519                 add_staging_flag(&buf, mod->name);
2520                 err |= add_versions(&buf, mod);
2521                 add_depends(&buf, mod, modules);
2522                 add_moddevtable(&buf, mod);
2523                 add_srcversion(&buf, mod);
2524
2525                 sprintf(fname, "%s.mod.c", mod->name);
2526                 write_if_changed(&buf, fname);
2527         }
2528         if (dump_write)
2529                 write_dump(dump_write);
2530         if (sec_mismatch_count) {
2531                 if (!sec_mismatch_verbose) {
2532                         warn("modpost: Found %d section mismatch(es).\n"
2533                              "To see full details build your kernel with:\n"
2534                              "'make CONFIG_DEBUG_SECTION_MISMATCH=y'\n",
2535                              sec_mismatch_count);
2536                 }
2537                 if (sec_mismatch_fatal) {
2538                         fatal("modpost: Section mismatches detected.\n"
2539                               "Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
2540                 }
2541         }
2542         free(buf.p);
2543
2544         return err;
2545 }